Microstructure, dielectric and microwave features of [Ni0.4Cu0.2Zn0.4](Fe2−xTbx)O4 (x ≤ 0.1) nanospinel ferrites
Tb-substituted Ni0.4Cu0.2Zn0.4TbxFe2−xO4 (0.0 ≤ x≤ 0.10) nanospinel ferrites were formed by sonochemical technique. It was first time established correlation between chemical composition of the nanosized NiCuZn spinels and their structural, electrical and microwave properties. The structure of nanospinel ferrites (NSFs) was proved through XRD. Microstructural were analyzed from SEM. It was observed a non-linear dependence of the average grain size with Tb concentration. The conduction mechanism and dielectric function has been extensively studied as functions of frequency, temperature, and Tb ions substitution ratio using complex impedance spectroscopy. It is obvious to see that the substitutions ratio showed a substantial influence on dielectric features, while Tb ion substitution has little but notable effect on AC/DC conductivity change. From the Arrhenius plots, the activation energies for all substitution ratios were calculated. The reflection losses as a function frequency dependences of the were calculated from S-parameters data within 1-4.5 GHz. The occurrences of the electromagnetic absorption in the frequency interval of 1.85-3.79 GHz were observed. Non-linear behaviour of the amplitude-frequency features were verified as a function of the level of chemical substitution (x) with Tb ions concentration. It was found microstructural parameters correlates well with the main absorption characteristics. It was discussed the nature of the electromagnetic absorption for partially substituted nanospinels. The decline of the reflected electromagnetic radiations was explicated along with domain-boundary resonance, which well correlates with the microstructure data. The low dimensional magnetic oxides having the domain-boundary resonance have a role in nature of absorption. © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). ; 2020-164-IRMC Islamic Azad University ; This work was supported by the Deanship for Scientific Research (Project application No 2020-164-IRMC) of Imam Abdulrahman Bin Faisal University (IAU–Saudi Arabia). The work was partially supported by Act 211 Government of the Russian Federation , contract No 02.A03.21.0011 (in South Ural State University).
